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pulmonary abscess
Etiology:
1) most frequently following aspiration of oropharyngeal contents containing large numbers of anaerobes
2) gingival & dental disease predispose to lung abscess formation
3) pathogens
a) anaerobic bacteria (30-50%)
b) aerobic gram-positive bacteria (25%)
c) aerobic gram-negative bacilli ( 5-12%)
4) opportunistic infections:
a) newborns with congenital cardiopulmonary disorders
b) elderly patients with blood dyscrasias
c) cancer of the lung or oropharynx
5) nosocomial/iatrogenic
a) steroid therapy
b) post-operative
6) hematogenous lung abscess
a) septicemia
b) septic embolism
c) sterile infarcts
Clinical manifestations:
1) foul smelling, purulent sputum
2) fever
3) weight loss
4) hemoptysis
5) cough
Laboratory:
1) leukocytosis
2) sputum culture for:
a) Mycobacterium tuberculosis
b) fungi
3) skin testing
4) bronchoscopy
a) if obstruction suspected from tumor or foreign body
b) cultures
c) drainage
Differential diagnosis:
1) tuberculosis
2) fungal disease
3) acute necrotizing pneumonia
a) Staphylococcus aureus
b) gram negative bacilli
4) carcinoma
5) vasculitis
6) septic embolism
7) pulmonary embolism with infarction
Complications:
- rupture into the pleural space causing empyema
Management:
1) drainage of involved segment
- postural with physiotherapy
- bronchoscopy may be necessary for abscess drainage
2) antibiotics
- penicillin G 1.5-2.0 million units IV every 4 hours; switch to Penicillin VK 500 mg PO every 6 hours once definite clinical response;
- continue until cavity closes
- ampicillin sulbactam
- clindamycin
- duration of therapy: at least 4-6 weeks
3) healing may take 6-12 months
4) surgical resection or percutaneous drainage rarely required
- persistent fevers & leukocytosis despite therapy
- bronchopulmonary fistula
- empyema
- hemoptysis (persistent)
- enlarging abscess cavity
- mechanical ventilation dependence
Related
empyema
General
pulmonary infection
abscess
References
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 253
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed)
Lippincott-Raven, Philadelphia, 1998, pg 799